<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <!-- 新 Bootstrap4 核心 CSS 文件 -->
    <link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/4.1.0/css/bootstrap.min.css">
    <!-- jQuery文件。务必在bootstrap.min.js 之前引入 -->
    <script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script>
    <!-- popper.min.js 用于弹窗、提示、下拉菜单 -->
    <script src="https://cdn.bootcss.com/popper.js/1.12.5/umd/popper.min.js"></script>
    <!-- 最新的 Bootstrap4 核心 JavaScript 文件 -->
    <script src="https://cdn.bootcss.com/bootstrap/4.1.0/js/bootstrap.min.js"></script>
    <title>首页</title>
</head>
<body>
    <center>
        <h1>请选择注册或登录</h1>
        <form action="login" style="margin: 5px;" method="get" id="form-main"><input type="submit"  class="btn btn-primary" value="登录"></form>
        <form action="register" style="margin: 5px;" method="get" id="form-main"><input type="submit" class="btn btn-primary" value="注册"></form>
    </center>
</body>
</html>